Massive Nitric Acid spill at the Austin Powder Red Diamond Plant in McArthur, Ohio Triggers Mass Evacuations, Grounds Flights

McARTHUR, Ohio — A massive nitric acid spill at the Austin Powder Red Diamond plant in McArthur, Ohio, unleashed chaos on Wednesday morning, June 11, 2025, prompting widespread evacuations, grounding flights across thousands of square miles, and casting an eerie orange plume over the region. The hazardous chemical leak, which authorities say involved approximately 3,000 gallons of nitric acid from a 5,000-gallon storage tank, has raised fears of health risks and environmental damage in Vinton County, roughly 185 miles east of the 2023 East Palestine train derailment disaster.

The incident, reported around 8:30 a.m. by a plant worker, occurred at a facility known for producing industrial explosives used in mining and construction. When nitric acid, a highly corrosive and toxic liquid, came into contact with the air, it triggered a chemical reaction, releasing nitric oxide—a noxious gas that formed a thick, orange-brown cloud visible for miles. “The plume looked like something out of a disaster movie,” said local resident Emily Conner, whose footage of the incident spread rapidly online.

The Vinton County Sheriff’s Office issued an immediate evacuation order for the nearby village of Zaleski, home to about 216 residents, directing people to seek shelter at Vinton County High School. “Leave now. Do not delay,” the sheriff’s office warned in a Facebook post, citing dangerous air quality. Surrounding areas were also placed on high alert, with road closures snarling traffic and schools evacuating students.

The Federal Aviation Administration (FAA) responded swiftly, imposing a no-fly zone spanning 3,700 square miles of airspace—more than twice the size of Rhode Island. Only emergency relief flights were permitted, as authorities sought to prevent aircraft from passing through the potentially hazardous plume. “This is a serious situation, and we’re taking every precaution,” an FAA spokesperson said.

Health officials urged residents to watch for symptoms of exposure, including eye and throat irritation, drowsiness, or even unconsciousness in severe cases. “If you’ve been exposed, flush your eyes and skin immediately and contact a healthcare provider if symptoms persist,” said Brad Price of the Vinton County Health Department. Nitric acid is known to cause severe burns and respiratory damage, and the orange haze raised comparisons to the toxic plumes that devastated East Palestine two years ago.

By late Wednesday, Austin Powder confirmed that the leak had been contained and emissions had ceased, allowing the evacuation order to be lifted for some areas. However, the sheriff’s office cautioned that the order could remain in effect overnight in certain zones, as hazmat teams and emergency crews continued to monitor the site. “The cloud is dissipating, and no injuries or deaths have been reported,” said Sheriff Ryan Cain, offering a glimmer of relief amid the crisis.

Meteorologists warned that falling nighttime temperatures could exacerbate risks by trapping the toxic gas closer to the ground, potentially intensifying exposure for downwind communities. “The boundary layer shrinks at night, which can concentrate the gas at the surface,” explained a Weather Channel report. Authorities pledged to monitor air quality closely, with winds blowing the plume northeast at about 5 mph.

The cause of the leak remains under investigation, with officials yet to determine how the tank failed. The incident has reignited concerns about industrial safety in Ohio, particularly in the wake of the East Palestine disaster, where carcinogenic chemicals contaminated soil and water.